Liquid heater and vaporizer



April 10, 1934. p: A Ls fi-,95 4,47l

LIQUID HEATER AND VAPORIZER Filed April 28, 1930 g 48 I '53 54 INVENTOR W m- E 5 1 FF'EED if. DANIELS Patented Apr. 10, 1934 LIQUID HEATER AND VAPORIZER H. Daniels,Worce-iter, Masa, asaignor to La Mont Corporation, New ,York, N. Y., a corporation of New York Application April 28, 1930, Serial No. 447,971

19 Claims.

This invention relates to liquid heaters and vaporizers,and more particularly to steam generating apparatus in which means is provided for creating a forced circulation of water through the heat exposed elements.

A steam generator of the type shown in the United States patent to La Mont Reissue No. 16,895 comprises a pump which draws water from a drum or other container and forces it into generating tubes exposed to the heat of a furnace. In such an apparatus an adequate supply of water to the tubes is essential inorder to prevent the tubes from reaching a dangerously high temperature; This has been recognized, and it has heretofore been proposed to utilize an auxiliary pump which will be placed in operation-automatically upon failure of the main pump to maintain the desired rate of flow. However, such an auxiliary pump with its driv-' ing means represents a considerable investment,

and even if used there is always a possibility that it will'become inoperative at a time when it is most needed. Similar problems arise in other types ofliquid heating apparatus.

It is accordingly themain object of my invention toprovide a simple and inexpensive, construction which will serve to insure an adequate flow of liquid through the heat exposed elements of a liquid heater whenever a condition occurs which tends to reduce the flow to the danger point, such as, for example, failure of the usual flow producing means to function properly.

It is a further object of my invention to provide a steam generating apparatus having heat exposed generating elements through which water is forced by means of a pump, and which is-so arranged that even though the pump or its driving means should fail a sufficient quantity of water will nevertheless be positively forced into the generating elements to prevent them from burning out.

With these and other objects in view, as will be apparent to those skilled in the art, my invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.

In accordance with my invention, I provide a liquid heating apparatus having heat exposed elements to'which liquid is delivered by a suitable means such as a pump. In order to protect the apparatus against overheating in the event that ,the flow for any reason falls below the amount required for protection, I'provide safety mechanism actuated in accordance withthe flow condltic ms which is eflective to alter the pressure arranged to deliver oil for, combustion through the tubes.

conditions in the system and to cause liquid to flow to the elements from a source of liquid and so protect them from overheating. In the preferred embodiment of my invention I utilize amechanism which upon reduction of the flow 00 to apredetermined amount serves to reduce the pressure at the discharge ends of the heating elements and thus permits liquid to flow through the elements from a supply at their inlet ends. This supply is preferably at such a pressure as will produce the desired flow.

Referring to the drawing illustrating one embodiment of my invention and in which like reference numerals indicate like parts:

Fig. 1 is a vertical sectional elevation of a 7 steam generating apparatus; and

Fig. 2 is an enlarged detail in section showing a portion of the inlet header and one of the generating tubes.

The drawing illustrates an embodiment of the inventionarranged for steam generation. It will be clear, however, from the following description that the invention may be used in connection with various other types of heat exchange apparatus. The embodiment illustrated comprises a furnace chamber 10 which is maintained 1 at a high temperature by any suitable means. For this purpose I have shown an oil burner 11 in the furnace in a well known manner.

A boiler 12 of any desired type is mounted above the furnace to absorb heat therefrom by radiation and convection; For simplicity of illustration, this boiler 12 has been shown as a horizontal cylindrical drum. forming a receptacle for water and steam under pressure. Water may be supplied to the drum 12 from any suitable source through a feed pipe 14, and steam may be withdrawn from the drum through a to a main steam header 16.

Adjacent to one wall of the furnace chamber 10 I have shown a water wall comprising spaced parallel horizontal tubes 18 arranged to generate steam by the absorption of radiant heat from the furnace and to protect the refractory mate- I00 rial of the wall behind them. The tubes 18 are connected at one end to a vertical pipe or inlet header 19, and at their opposite ends to a vertical'outlet header 20. v A suitable forcing means, such as a centrifugal pump 22 driven by an electric motor 23, is provided to circulate water A pipe 24 is connected to the drum 12 below the water line and leads to the inlet of the pump 22. The discharge of the pump pipe 15 leading is connected to the inlet header 19 of the water wall. The outlet header 20 is connected by a pipe 26 with the steam space of the drum 12.

With this construction the pump 22 draws water from the drum 12 through pipe 24 and delivers it under pressure to inlet header 19 and tubes 18. The steam which is formed in the tubes, together with any unevaporated water, passes back to the drum 12 through header 20 and pipe 26. The

entrance end of each tube 18 is preferably restricted by means of an orifice plate 27 (Fig. 2) for the purpose of properly distributing the water among the tubes.

The present invention as applied to the construction so far described is primarily concerned with an arrangement for continuing the supply of water to tubes 18 in the event pump 22 should fail to function properly. The invention is thus in the nature of, a safety device to protect the tubes from overheatir'g under these circumstances. In order to accomplish my purpose, I provide means automatically actuated upon failure of pump 22 which serves to close oif the outlet header 20 from drum 12 and also to relieve the pressure in this header,-for example by permitting the header to discharge tq a lower pressure and preferably tothe atmosphere. The pressure in drum 12 is then effective to force water through pressure in the chamber under these conditions.

the tubes 18 connected thereto.

In the specific embodiment illustrated I have shown an emergency discharge or exhaust pipe 29 leading from pipe 26 to atmosphere or to any suitable point for discharge of water and steam at a lower pressure than that of the boiler 12, such.

as the blow down system for example. A valve 30 in pipe 29 normally prevents flow therethrough.

An orifice plate 31 may also be provided in pipe 29 to limit the rate of "flow, in case valve 30 is open, to an amount slightly inexcess of that necessary to protect the tubes 18. A check valve 32 located in pipe 26 between pipe 29 and the boiler prevents the discharge of steam from the boiler through pipe 29 when valve 30 is open. This check valve may be of the ordinary swing type having a valve member 33 pivoted to the body portion of the valve and arranged to be held open by the normal flow in pipe 26 in the direction of the drum and to close tightly against its seat whenever the flow tends to reverse its direction.

Various constructions may be utilized within the scope of my invention to open valve 30 automatically in the event pump 22 should fail to maintain the desired rate of flow. The preferred arrangement illustrated has been fully disclosed in the prior application of Charles M. Terry, Serial No. 445,978, and comprises a flexible diaphragm 34 connected directly to valve 30 by a rod 35. The diaphragm is subjected to the fluid PIGS? sure in a diaphragm chamber' 37, and this pres-' sure is opposed by a compression spring 38 and by the boiler pressure which is normally effective beneath the valve. It will thus be seen that the the spring 38 serves to bias valve 30 toward open position, and the valve will remain closed only so long as the pressure in chamber37 exceeds a predetermined amount.

The preferred construction for controlling the fluid pressure in chamber 37 comprises a casing 40 shaped to form a chamber 41 which is connected to chamber 37 by means of a pipe 42. A pipe 44 leads from inlet header 19 to chamber 41, and the fluid pressure in the inlet header is thus normally effective in chamber 37 to hold valve 30 closed. Chamber 41 is provided with an outlet passage leading to a discharge pipe 46, which may be connected to a drain, and the flow through the outlet passage is controlled by a valve 47 which is normally held closed so long as the proper flow is being maintained through the generating tubes 18 by pump 22.

In order to obtain the desired automatic operation I provide a flexible diaphragm 48 connected by a rod 50 to the valve 4'7 and preferably subjected to a fluid pressure differential which is a function of the rate of flow in the tubes 18. Such a presure differential exists as a result of the orifice plate 27 at the entrance of each generating tube, and may be utilized by connecting a pipe 51 teone of the tubes 18, as shown in detail in Fig. 2, and leading this pipe to a chamber 53 beneath the diaphragm 48. The pressure in chamber 41 is made effective above the diaphragm. so that the pressure differential between the header 19 and tubes 18 tends to hold valve 4'! closed. A compression spring 54 beneath the diaphragm 48 serves to oppose this pressure differential and to bias the valve 47 toward open position. The valve will therefore open whenever the rate of flow and the resulting pressure drop falls below a predetermined value. An oriflce plate 56 is preferably provided in pipe 44 to restrict the flow into chamber 41 when valve 47 is open, and thus prevent the building up of A valve 57, normally operable bymeans of a hand lever 58, is preferably located in the outlet and check valve 33. .1111; pressure differential on opposite sides of plate 27. will be effective on diaphragm the valve 47 will thus be held closed. The inlet header 19 will thereforebe 34 to hold valve 30 clam ,Yalv'e 57ft; held open by spring 60.- If 'nowthe flowof water from'the pump 22 should stop for anyreason, such as a failure of the electric supply to the motor 23, the v flow into the tubes 18 and the resulting pressure differential effective upon diaphragm 48 will decrease. Under these conditions spring 54 will open valve 47 and permit fluid to flow out of pipe 46, thus relieving the pressure in chamber 41, pipe 42 and chamber 34, and permitting spring 38 to open the valve 30. This will cause steam to flow out through the exit pipe 29 and relieve the pressure inthe tubes 18. Check valve 32 will clue to prevent escape of steam from the boiler 12, and the steam pressure in the boiler will now force water through pipe 24', pump 22,

header 19, tubes 18, header 20, pipe 26, and pipe 29 at a rate sufficient toprotect the tubes 18 from burning out. In the meantime the oper-,'

ator can shut down the oil burner 11 and correct the difficulty which causedffailure of pump 22.

With valve 47 open, orifice plate 56 limits the flow through pipe 48 to a" slight amount and prevents the building up of pressure in chamber 41. After pump 22 has been placed in operation once more,,the operator can close valve 57 by hand. Pressure will then build up-in chamber driving means.

41 until it the'inlet header pressure, valves A liquid heating apparatus comprising liquid and 47 will close, and valve 57 maythenbe opened without relieving the pressure in. cham- It will be seen that the present invention vides a reliableand effective protection for steam generating apparatus and other types of liquid heaters in, which an .adequateflow of liquid is,

essential for their continuedoperation. The 0011': struction is simple and inexpensive to manufac ture, and does not require auxiliary pumps. or

Having thus desc ibed my inventionywhat I claimas new and desirento secureby Letters Patent'is: i

1. A liquid heating apparatus comprising ele-! ments carrying fluid, under pressure which, are arranged to be exposed to heat, a dischargecon-a nection therefrom, means'connectedto said elementsand providing asupply-ot liquid under pressure, a pump-arranged normally to deliver to, said elements the liquid to-be heated, .and

means, for co fi ing and ,controlling, the fluid carriedby said elements and arranged to be actuated upon failure of said pumpto exhaust fluid from said dischargeconnection and thereby to reduce the: pressure therein suillciently tc causesaid liquid supply pressure to "deliver liquid toithe elements. I i

elements and providinga supply'oiliquid under pressure, a pump to deliver to saidelements the i liquid to be heated and fluid control means ar.

ranged to be actuated seas; automatically to ex-,

haust fluid from said discharge connectionwhenever the rate atwhich liquid is delivered to the elements by the pump falls below a predetermined amount andthereby to reduce the pmthereinsuflioientlyto cause said liquid supply pressure to deliver liquid to the element. i

ceptacle containing liquid under pressure, elements arrangedto ,be,exposed to heat and to carry fluid underpressure means to deliver liquid from the receptacle to the elements, an en-J haust pipe connected to'said elements, a valve 1 in said pipe which; is-normally closed-and .actuat'edby a ,iorce caused by flow 'ofthef. liquid to the elements and acting when the rate of flow or liquid to the elements falls below a predetermined amount to" open the valve and lower the pressure in the exhaustipipe sumciently to cause the pressure in said receptacle to force said liquidirom the receptacle into said elements wherebyto restore the flow oi liquid from the re-;

ceptacle into the elements.

4. A liquid heating apparatus comprising a re-, ceptacle containing liquid under pressure, elements arranged tobe exposedto heat and to carry fluid under pressure, means to deliver liquid from said rate lowering below a predetermined amount,

, will operate tolopen the valve and lower the pres-,

sure in the elements sufllcientlyto cause the pressure 'in the receptacle to torcethe liquid therein into said elementsand thereby restore the flow oi 12116 5 1 111 the receptacle.

the rate of flow falls below a predetermined heating elements arranged to be exposed toheat, means connected to said elements and providing a, reservoir of liquid under pressure, means to supply liquid under pressure to said elements, means providing a discharge outlet from the elements. and means responsive to-varlations in a force causedby the flow of liquid to the elements which is effective to open the discharge whenever amount and thereby to reducethe pressure therein sufllciently tocause a flow of liquidfrom said reservoir-through said elements in amount willi cient to protect the elements.

.liquid from the tubes to be discharged to n. pressure less than that in the receptacle, whereby the" pressuretin the receptacle will force liquid-into thetubes; l I

7.:Steam generating apparatus comprising a drum containing water under pressure, a plurality of tubes arranged to beexposed to the heat or a furnace, a pump to deliver water irom the drum' to the tubes for evaporation-therein, a steamdis-l'lil charge connection for the tubes normally carry-l ing the :steam ata pressure substantially equal to that in the drum; and fluid pressure reducing means connected and arranged to reduce the pres! sure in thedischarge connection automatically upon failure of. the pump to supply water to the tubes at a rate in excess of a predetermined amount and sufliciently to cause the pressure in 3. A liquid heating apparatus r sins a me.

the drum to force water into the tubes. 1

8. Steam generating" apparatus comprising e boiler, alurnace arranged to suppLv heat to the boiler and generatesteam under pressuretherein,

a plurality of tubes forming a waterwallexposed tothe'radiant heat 01 the iumace, a pump arranged to withdraw water-(1mm the boiler and deliver ittozthe tubes. a connection between the discharge lot the tubes and (the boller through :whieh steam and any unevaporated 1 a I water from the waterwall tubes are normallyre-w turned to .the boiler, and valvular means associated withsaid connection and arranged to be eflective,: upon failure of the pump to deliver waterrto the tubes at a ratefinexcess of a -predetermined amount, to cause discharge of the steam and any unevaporated water from the water wall tubes to the. atmosphere instead oi to' the boiler I and concomitantly to cause the steam pressure in e the boiler to force water: into thetubes. the receptacle to the elements, an exhaust pipe connected tosaid elements, a valve in said pipe which is normally closed, and a device actuated:

' by a pressure causedby the flow of the liquid to said elements and controlledin relation to the 1 rate of flow or liquid to the elements which, uponranged to withdraw water from the boiler and deliverit to the tubes, anoriflce plate at the entrance 0! each tube restricting the flow thereto, a

connecting pipe to convey steam and any unevap orated water from the water wall tubes back tothe boiler, abranch pipe leading from the connecting .pipe to the atmosphere and having a valve them 150 in, means to open the valve automatically whenever the rate of flow into the tubes falls below a predetermined amount, thereby causing the steam pressure in'the boiler to force water into the tubes and protect them from burning, and a check valve in the connecting pipe between the branch pipe and the boiler to prevent the escape of steam from the boiler when the valve is open.

1 0. A heat exchanger having heat exchanging surfaces, means normally effective to cause a liquid to flow in heat exchanging contact with said heating surfaces to produce aheated fluid, means providing a reservoir supply of liquid under pressure connected to the heat exchanging surfaces so as to supply liquid thereto, fluid control means constructed and arranged to be effective upon a predetermined change in the operation of the means normally causing flow of the liquid in said heat exchanging contact to cause the pressure of said liquid in said reservoir to deliver the liquid to said heat exchanging surfaces and cause it to flow in heat, exchanging contact therewith. Y

11. A steam generating apparatus comprising a steam generating tube, means normally effective to deliver water to one end of said tube in quantity in excess of the evaporation therein, means at said end of said tube for limiting the quantity of water delivered to the tube to an amount insufllcient to flll the cross sectional area of the tube, so as to leave space within the tube for the steam, said limitation normally creating a pressure diflerential in the water flow, a discharge connection from said tube, means providing a storage volume of water under pressure connected to said water inlet end oflthe tube, and fluid control means constructed and arranged to be operated by said diflerential pressure and to be effective upon a predetermined change in said differential pressure to reduce the pressure in said discharge connection sufficiently to cause water from said storage volume to be delivered through said water limiting means to maintain, the flow of water through the tubes in excess of the steam generated therein.

12. Heat exchange apparatus comprising aliquid heating element exposed to heatymeans normally providing flow of liquid to said element, means connected to said element for withdrawing heated fluid therefrom during normal flow of liquidthereto, fluid controlmeans also connected to said element normally preventing flow through itself of the heated fluid but arranged when actuated to cause flow therethrough of said fluid, means acted upon by a force derived from the flow of the :liquid to said element and arranged to actuate said fluid control means when the delivery of the liquid to the element corresponding to normal withdrawal of, the heated fluid is reduced below a predetermined amount, and a supply of liquid under pressure connected to said element and so arranged in connection with said fluid control means as to cause flow of liquid to said element from said supply to tend to restore said normal flow upon actuation of said fluid control means. i

13. Heat exchanger comprising means providing a supply of liquidunder pressure, a heat exchanging surface, liquid delivery means connected and arrangedv to withdraw liquid from said liquid supply and deliver it to said heat exchanging surface to produce by heat exchanging contact with said surface a heated fluid, means for so confining said heated fluid as to maintain it at a pressure normally not less than the pressure of said liquid supply, fluid pressure control means actuated in accordance with variations in a force derived from the delivery of the liquid to said heat exchanging surface and arranged to reduce the pressure of said heated fluid when said liquid delivery is "reduced "below a predetermined amount, the'arrangement of said liquid supply and said heat exchanging surface'and said fluid pressure control means being such as to cause the pressure of said liquid supply to deliver liquid to said heat exchanging surface and to discharge the heated fluid therefrom to said reduced pressure uponactuation of said fluid pressure control means when said liquid delivery is reduced belowsaid predetermined amount.

14. Heat exchange apparatus comprising a receptacle containing'liquid under pressure, a tube exposed to heat, means connected to deliver liquid to the tube and to cause said liquid to flow through said tube to produce a heated fluid under pressure, and fluidpressure reducing means actuated -in' accordance with a predetermined variation in the rate of delivery of the liquid to the tube and arranged to reduce the pressure of said heated fluid upon reduction of said rate ofdelivery belowa predetermined amount, said receptacle and said fluid pressure reducing means being so connected to said tube that upon reduction of the pressure of the heated fluid the pressure in the receptacle is effective to deliver liquid 105 therefrom to the tube for flow therethrough to produce the heated fluid.

15. Steam generating apparatus comprising a drum containing water subjected to the pressure of the generated steam, a plurality of tubes exposed to steamgenerating heat, a pump to deliver from the drum vto the tubes at one end thereof the water to be evaporated into steam therein, a steam collector connected to the other ends of the tubes to collect steam from said tubes andto deliver it to the steam space of the drum and arranged so as normally tohave a pressure therein not less than the pressure ofthe steam in the drum, fluid pressure reducing means connected to said collector and arranged to be actuated automatically, upon failure of the pump to supply water to the tubes at a rate in excess of a predetermined amount, to reduce the pressure in said collector below the pressure of the steam in said drum, and fluid flow control means arranged to cause said steam pressure to force water from the drum into tubes for flow therethrough toward said collector while preventing reverse flow of steam from said drum to said collector. Y

16. A fluid heating apparatus comprising an element arranged to be exposed to heat, means for normally delivering to said element the fluid to be heated, means so connected to said element and providing a volume of fluid in such condi- 135 tion of pressure that fluid is capable of flowing from said volume of fluid to said element in like and arranged to reduce the pressure in said discharge connection relative to that ofthe volume said volume of fluid to said element upon said change in the normal flow.

17. A fluid heating apparatus comprising an element arranged to be exposed to heat,-means for normally delivering to said element the fluid to be heated, means providing a volume of fluid under pressure so connected to said element that under said pressure fluid may flow from said volume of fluid to said element in like manner to said normal flow, a discharge connection from said element, means including fluid control means and responsive to variations in a force derived from the flow of fluid to the element and arranged to create a difference in pressure between the pressure of said volume of fluid and the pressure within said discharge connection such as will cause flow of fluid from said volume of fluid to said element upon a predetermined change in the normal flow of fluid to the element.

18. A liquid heating apparatuscomprising elements arranged to be exposed to heat, a discharge connection therefrom, means connected to said elements and providing a reservoir supply of liquid under pressure, means normally effective to deliver to said elements the liquid to be heated therein to produce the heated fluid, and

fluid control means automatically responsive to failure of said delivery means to cause said reservoir supply means to be connected through said elements and said discharge connection to a reduced pressure sufiiciently below that of the liquid in said reservoir to maintain a constant supply of said liquid through said elements.

19. A liquid heating apparatus comprising elements arranged to be exposed to heat, means connected to said elements and providing a volume of liquid, means to supply liquid to said elements, a discharge connection from said elements, and means responsive to variations in a force derived from the flow of the vliquid to said elements including fluid control means arranged to relieve the pressure from the discharge connection whenever the rate of flow of said liquid decreases below a predetermined amount and thereby to reduce the pressure therein sufliciently to cause a flow of liquid from said volume through said elements suflicient to protect the elements.

FRED H. DANIELS. 

